Oscillation generator



sept. 1s, 1930.

w. H. EDWARDS 1,775,752

oscILLATIoN GENERATOR Filed lay 14, 1929 INVENToR ATTORNEY Piuma sept. 16, 1930 UNITED STATES PATENT OFFICE WILLIAM H. 0F GREAT NEGK, NEW YORK, ASSIGNOR T0 AMERICAN TELE PHONE .AND TELEGRAPH COMPANY, A GQBPOBATION 0F NEW YORK OSCILLATION GENERATOR Application viiled May 14,

This invention relates to a method of and means for varying the impedance of an element and more particularly to the utilization of such principles and apparatus as an oscillation generator.

In the operation of the arrangements of the invention, a 'device'such as a thin film rectier, forV example, a disk of copper and cuprons oxide, is included in a circuit and subjected to external stress. It has been found that subjecting a device of this characier to stress will vary its impedance in the circuit. En accordance with the arrangements ci this invention, the stress to which thedevice is subjected is caused by utilizing itas a vibrating reed armature under. controt of a relay incircuit therewith. Under such conditions, the impedance in the circuit may he constantly varied and `the device may he utilized as an oscillation generator. Other objects and features of the invention `will ap# gear more fully from the detailed'description thereof hereinafter given.

For pin-poses of illustration, it will be assinned the element whose impedance vis to he varied by the method of this invention,

may he a rectier of the Well known copper oxide type. However, other types of thin lm or Contact rectifiers may be utilized. Une ci the suitable methods of forming the rectifier element might consist in lieating a copper sheet ahout .095" thick to over 1000 C. until a thin cosely adherent layer of cuprous oxide about one or two thousandths of an inch is formed. A heat treatment is then administered at iower temperatures. The outer surace'oi the oxide may then be reduced to metaliic copper hy electrolysis. The impedance element in the circuit might be formed or one or more of such units.

.i the iunction of the bulk of the cuprous oxide and the mother copper there is believed oxide crystals mate rcrystals which they adjoin., This transition to he a transition la er, wherein the copper perfectly the copper layer is of high resistivity but in formation, is made to match on to the copper in such a way (probably with considerable stress in the transition layer) as to reduce to a low` value the work function of escape into it of 1929. serial no. 363,086.'

electronsl` from the copper. matches on to the adjoining cuprous oxide in However, it

such a way as to make a large work function.

due to the different manner in which it is Y.

formed. Based on the theory of a transition layer depending upon initial stresses or on substantially perfectly matched crystals, it is proposed in accordance with the principles of this invention, to vary the stresses in this transition layer or the manner in which the crystals are matched and thus vary the work functions. inasmuch as the oxide and surface coating of copper are very thin, the transition layer is near the surface of the rectifier plate and is subject to aproximately the maxiinum fibre stresses existing in the plate when it is iiexed. Furthermore, when a portion of the plate bends in one direction, they transition layer has tension stresses superimposed on the initial stresses, and when bent the other way, has compression stresses added to it; .It has been found by experiment that bending a plate sothat the oxide is placed in tension instantly increases the resistance in the reverse direction and that when placed in compression, the opposite occurs. It has also been found that variations in pressure cause variations inresistance in the conductmagnet 8, and a stressed thin iilm rectifier disk 2. This rectifier disky has had its thickness exaggerated in the drawing for purposes of illustration and may be composed of a copper portion 3, and oxide film 4 and a surface flash of copper 5. Other metals than copper might be utilized in the construction of the rectifier disk however. The disk is cuit, and an output vcircuit'co'nnected to said held by twosupport members 6 and 7, which circuit. are in contact wlth different sides of the disk In testimony whereof, I vhave signed my and are connected to the line. At or near name to this specification this 11th day of f the extremity of the disk and in proximity' May 1929. i 7o j to the pole plece of magnet'S, is an armature WILLIAM I I. EDWARDS.

9 axed tothe end of the disk. When the v switch 15 is closed, the magnet 8 is energized through the rectifier disk 2 and attracts the ,a

lo magnetic amature 9 on the end of the disk. 75

This will bend the disk over to lthe position l indicated by the dotted line 10. Thls bending ofthe disk will increase the rectifier re'- sistance andhence decrease the pull of the 15 magnet on armature 9. Accordingly, the so disk will swing back to the position shown by dotted line 11. This bending orstressing of the disk in the other direction will decrease the vrectifier resistance, thus increasing the s 20 current in the circuit and the pull of the magsa net and the disk will swing back a ain. In other words, the disk will swing ack and .forth like a vibrating reed and the stresses to which it is subjected in bendingin each direction will increase and decrease the re- Vim sistance and the direct current iiow in the 1 circuit 1. These changes in the direct current induce an alternating current voltage in the secondary of transformer 13.

An oscillator constructed' on the above 95 principles has the advantage of'constancy of frequency with smoothness of wave shape, combined with low vfirst and maintenance cost. It is pointed out that the output cir- 85 cuit. will produce alternating current corre- 100 spending in frequency tothe period of vibration of the rectifier disk and that this is capable of adjustment.

While the invention has been disclosed as 40 embodied in certian specific arrangements 105 `which are deemed desirable, it is understood that it is capable of embodiment in many and other Widely varied forms without departing from the spirit of the invention as ldiafined by the appended claims. '110 What is claimed is: o l 1. A circuit comprising a source of current and a magnet, astressed thin film rectifier disk included in said circuit, said disk being firmly fastened at one extremity'andhaving- 115 its other extremity so related with respect to saidmagnet that it will be caused tovibrate thereby thus varying the stress to which it is subjected and its relative impedance in said circuit. v

, 2. An oscillation generator'comprising a circuit including a 'sourceof current and a magnet, a stressed thin film rectifier disk im eluded in said circuit and being firmly fas- ,25 tened at one extremity and having its other extremity so positioned with respect to said magnet that it will be caused to vibrate thereby thus varying the stress to which it is sube5 jected .and its relative impedance in saidcir- 

